I wouldn't count on it. As long as the product is available and marketed in other countries they can get caught in legal issues for not following those countries laws relating to marketing and offering of products.
Darktable is open source, though; it's not really offering a commercial product. Besides, what will eurocrats do if they determine a copyright issue? It's not as though there will be any earnings to garnish, worst-case scenario. If I (an American) publish a software project, Euro trademark law doesn't apply to me.
Legally does it really matter what is your specific price point or development model? Also it does nor matter what is your residency, if you publish it in Europe (or country X) then at least in theory you need to follow the local laws. How/if these would be enforced is another question. And yes I know your publishing tool probably does not even give you much control to which countries you start to export your product once you click Publish. Or is there any such at all?
